Determining soil strength of unconsolidated deposits using surface waves; exploring possibilities for testing consolidation of tailings ponds

摘要

For the production of oil-sands in Alberta, Canada, large quantities of sediments are excavated daily to extract the bitumen. The tailings of this extraction process that have been stored in confined disposal facilities (tailings ponds) show lower rates of consolidation than expected. These low consolidation rates are associated with the heterogeneity of the mined deposits and the segregation between the sands and the finer fraction during the hydraulic fill process of the ponds. Limited consolidation rates of specifically the fine sediments result in an increase in volume of the final deposit, sensitivity to liquefaction, and a reduced bearing capacity, preventing land reclamation. Although attempts have been made to design non-segregating tailings (e.g. Pennekamp, et al., 2010; Van Kesteren, et al., 2007) to counter consolidation problems, it remains a challenge to determine the in-situ consolidation for individual tailings ponds, causing delays in land reclamation programmes.